Improvement



ldlnitrh 4tsirs gstrlnt' @fitta IMPROVEll/IEN'Iv IN ADJUSTABLE SPIEITrLEVELS.

@Le Stimme maar tu yim ilgese tettets rt'ent mit mating @zut at tige same.

TO ALL WHOM IT MAY CONCERN;

Be it known that I, WILLIAM J. TATE, of New Haven, in the county of New Haven, and State of Connectieut, have invented a new and improved Adjustable Spirit-Level; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in theart to make and use the same, referencevbeing hadto the accompanying drawings,V forming part of this specification.

Figure 1 represents a vertical longitudinal section of my improved spirit-level.

Figure is a horizontal'sectional view ot' the same, the plane of section being indicated by the line xm, tig. 1.

Similar letters of reference indicate corresponding parts. I i

This invention relates to a new spirit-level, which is so arranged that it can be reset with great ease when not quitecorrect. The ordinary levels now in.use are not very correct, and cannot remain'correet, even when made so. The least expansion or contraction ofthe metal, the least shrinking ofthe wood, a shock occasioned by a fall or otherwise, will make the instrument incorrect, and, therefore, totally useless, until reset. The levels now in use cannot very conveniently be reset, when once deranged, and can certainlyrnot-bc reset instantaneously by every mechanic. By the use of my invention, the level can be instantaneously-set-accurately in its case by any person, no ingenuity being required for the purpose.

A represents the case of'a level, made of wood, or .other suitable material. It is recessed, to receive a metal box B, in which the ordinary glass bulb C is held.A i The box B has at its ends perforated projecting plates a a, through which screws b' are itted, th'sa'id screws being suspended-from the covering-plate D of the case. The lower ends of the screws b :are secured in nuts, 'c c, in such a manner that the projections .a of the box B, and with them the box B, rest' upon the said/nuts. The nuts are square or polygonal, and t in the recess of the case, so that they cannot turn therein, but can slide up and down. Spiral -or other springs, el d, are or may' be arranged between the plate D and the projections a, or other part-s of the box B. The springs force the box i3, and with it the bulb C, upon the nuts.

When the level is to be set true, the screws b b are turned until the box D is brought into. the right position, so that the air-bubble inthe bulb will be inline with the centre mark of the plate. i

This invention may also be applied with advantage for laying out sloping grades, as the level could be adjusted to the required angle by means of a suitable instrument, and then the bubble will be in line with the mai-kpn the plate D, whenever the level is set at the required angle.

. I claim las new, and desire to seeureiby Letters Patent- 1. The adjustable spirit-level, consisting ofthe box B, provided with the perforated projections a, through which the screw-bolts surrcjinded by the springs al, pass, and the adjusting-nuts c, working in the recesses of the ease A, as herein described, for the purpose speciied.

2, The combination of the adjusting-nuts c and springs d with the perforated anges a of the box D, and the serew-bolts b, as herein described, for the purpose specified.

WILLIAM J. TATE.

Witnesses:

CHARLES T. Sri-ELTON, Geo. F. GARDINER. 

